Reworking device for removing electrical elements mounted on motherboard

ABSTRACT

A reworking device ( 10 ) for removing a socket connector ( 20 ) soldered to a PCB ( 40 ) comprises a body portion ( 12 ) and a pair of movable clips ( 16 ) assembled to the body portion. Each of the movable clips has a hook ( 16   f ) for hooking a portion of the socket connector. A spring ( 16   e ) is compressively mounted on each of the movable clips for providing an upward force to the hook to pull the socket connector upwardly from the PCB when a soldering connection between the PCB and the socket connector is heated to reflow. A pair of standing legs ( 14 ) is provided to stand on an upper surface of the PCB beside the socket connector. The body portion is mounted on the standing legs.

CROSS-REFERENCE TO RELATED APPLICATION

[0001] This patent application is a Co-pending application of patentapplication Ser. No. 10/170,989, entitled “REWORKING DEVICE FOR REMOVINGELECTRICAL ELEMENTS MOUNTED ON MOTHERBOARD”, filed on Jun. 11, 2002,invented by the same inventors and assigned to the same assignee as thispatent application.

BACKGROUND OF THE INVENTION

[0002] 1. Field of the Invention

[0003] The present invention relates to a reworking device, and moreparticularly to a reworking device for lifting an electrical elementfrom a motherboard to which the electrical element is soldered tothereby remove the electrical element from the motherboard.

[0004] 2. Description of Prior Art

[0005] Surface mounted electronic elements have become a trend incomputer industry, since they have a number of advantages over throughhole mounted elements. For example, a socket connector for electricallyconnecting a central processing unit (CPU) to a motherboard has beenevolved from pin grid array (PGA) to ball grid array (BGA) so as tobenefit the advantages of SMT, such as automatic mounting of theconnector on the motherboard.

[0006] However, one problem associated with the BGA socket connector andother surface mounted elements is how to remove the mounted BGA socketconnector or the like from the motherboard when the connector or thelike or the connection thereof with the motherboard is found defective.

[0007] As a matter of fact, a typical BGA socket connector generallyincludes more than four hundred solder balls arranged in a matrixcovering a entire bottom surface of the connector. For the PGA socketconnector, the rework thereof, i.e., removing the mounted PGA socketconnector from the motherboard, can be done by reflowing the solderslocated between the pin legs of the socket connector and the throughholes in the motherboard and access them from the bottom of themotherboard. However, for the BGA socket connector, it is unlikely toaccess the solder balls located under the socket connector and applyheat to the solders to reflow them thereby separating the BGA socketconnector from the motherboard.

[0008] Once the mounted BGA socket connector or the like or thesoldering thereof to the motherboard is found detective, the connectoror the like together with the mother board has to be thrown away. For areference, the estimated cost for a motherboard is at least US $50 andeven more for high-end motherboard. The throw away of the entiremotherboard only because of a defective element thereof or a defectivesoldering of an element thereof inevitably increases the overallmanufacturing cost.

[0009] In order to remove the mounted BGA socket connector or the likefrom the motherboard, a main problem to be solved is how to effectivelyapply a uniform pulling force to the connector once a solderingconnection of the connector with the motherboard is released.

SUMMARY OF THE INVENTION

[0010] An objective of the present invention is to provide a reworkingdevice which can lift a BGA socket connector mounted on a motherboardsuch that the BGA socket connector is completely detached from themotherboard once solder balls of the connector are heated to reflow.

[0011] A further objective of the present invention is to provide areworking device which can lift a BGA socket connector mounted on amotherboard effectively without damaging the motherboard.

[0012] In order to achieve the objectives set forth above, a reworkingdevice for removing a surface mounted socket connector from amotherboard comprises an elongate body portion, a pair of standing legsand a pair of movable clips. The standing legs are set on themotherboard beside the socket connector. The elongate body portion ismounted on the standing legs and located above the socket connector.Each of the movable clips is hanged on an end of the body portion andincludes a hook at a bottom end thereof engaging with the socketconnector. Each movable clip has a spring. The springs can expand toactivate the movable clips to move upwardly, thereby to pull the socketconnector upwardly from the motherboard, when a soldering connectionbetween the socket connector and the motherboard is heated to reflow.Thus, the socket connector is separated from the motherboard.

[0013] Other objectives, advantages and novel features of the inventionwill become more apparent from the following detailed description of thepreferred embodiment when taken i0n conjunction with the accompanyingdrawings.

BRIEF DESCRIPTION OF THE DRAWINGS

[0014]FIG. 1 is a top view of a reworking device of the presentinvention;

[0015]FIG. 2 is a cross-sectional view of the reworking device of FIG. 1and a socket connector and a printed circuit board (PCB) on which theconnector and the reworking device are mounted; and

[0016]FIG. 3 is a view similar to FIG. 2, showing the reworking devicebeing activated to lift the socket connector from the PCB.

DETAILED DESCRIPTION OF THE INVENTION

[0017] Reference will now be made to the drawing figures to describe thepresent invention in detail.

[0018] Referring to FIGS. 1 and 2, a reworking device 10 of the presentinvention is used to separate a surface mounted BGA (Ball Grid Array)socket connector 20 or the like from a printed circuit board (PCB) 40which usually is a motherboard. The socket connector 20 includes arectangular base 22 and a cover 26 slidably mounted on the base 22. Aplurality of solder balls 24 arranged in a matrix is attached on abottom face of the base and soldered to the PCB 40. The solder balls 24are attached to bottom ends of conductive terminals (not shown) of thesocket connector 20. The cover 26 includes a pair of protrusions 26 a atopposite sides thereof.

[0019] The reworking device 10 includes an elongate body portion 12, apair of standing legs 14 downwardly located at two opposite ends of theelongate body portion 12, and a pair of movable clips 16 movablyassembled to the body portion 12 and engaging with the protrusions 26 aof the socket connector 20. The elongate body portion 12 defines anelongate slot 12 a longitudinally extended therealong, and an enlargedround hole 12 b at a middle of the elongate slot 12 a. The elongate bodyportion 12 further defines a receiving hole 12 c in each of the twoopposite ends thereof. Each of the standing legs 14 includes a post 14a, an enlarged portion 14 b at a bottom end of the post 14 a abuttingagainst the PCB 40, and a screw (not shown) is formed on an upper end ofthe post 14 a. A nut 14 c is screwed downward along the screw of thepost 14 a of the standing leg 14 and a first spring 14 d is locatedsurrounding the post 14 a. The first spring 14 d has a top end abuttingagainst a bottom face of the elongate body portion 12 and a bottom endabutting against a top face of the enlarged portion 14 b of the standingleg 14. In addition, a soft pad 28 is provided on a bottom face of eachof the enlarged portions 14 so that the soft pads 28 are located betweenthe enlarged portions 14 b and the PCB 40. Each of the movable clips 16includes a straight pole 16 a, a first washer 16 b fixed at an upperportion of the pole 16 a, a second washer 16 c fixed at a lower portionof the pole 16 a, and a third washer 16 d assembled to the pole 16 abetween the first and second washers 16 b, 16 c and being able to movealong the pole 16 a. Each washer 16 b, 16 c, 16 d has a diameter whichis larger than a width of the slot 12 a, but smaller than that of theenlarged hole 12 b of the elongate body portion 12. A second spring 16 esurrounds the pole 16 a between the first and third washers 16 b, 16 d.Each of the movable clips 16 includes a hook 16 f at a bottom endthereof.

[0020] Also referring to FIG. 2, in use, first, the standing legs 14 arelocated beside the socket connector 20 which is mounted on the PCB 40and is to be removed therefrom since an incorrect soldering existsbetween the connector 20 and the PCB 40. The first springs 14 d arebrought to surround the posts 14 a of the standing legs 14, and the nuts14 c are not screwed onto the posts 14 a. The movable clips 16 are thenassembled to the elongate body portion 12 through the enlarged hole 12 band moved to two opposite ends of the slot 12 a. The third and thesecond washers 16 d and 16 c are located respectively at above and belowthe body portion 12. Thereafter, the elongate body portion 12 with themovable clips 16 is attached to the standing legs 14 with the posts 14 aof the standing legs 14 extending through the receiving holes 12 c ofthe elongate body portion 12 and the elongate body portion 12 abuttingagainst a top end of the first springs 14 d. The nuts 14 c are screwedto the posts 14 a of the standing legs 14 to secure the elongate bodyportion 12 to the standing legs 14. The movable clips 16 are thendownwardly pressed enable the hooks 16 f to firmly engage with theprotrusions 26 a of the socket connector 20. The second springs 16 e arethus compressed to provide the socket connector 20 an upward forcethrough the hooks 16 f of the poles 16 a. Finally, the socket connector20, the reworking device 10 and the PCB 40 are together moved through anoven (not shown) to soften the solder balls 24 between the socketconnector 20 and the PCB 40. When the solder ball 24 are sufficientlyheated to reflow, the socket connector 20 is pulled up by the expansionforce of the springs 16 e. Thus, the incorrectly mounted socketconnector 20 is removed from the PCB 40. The movable clips 16 pull thesocket connector 20 upwardly until the second washers 16 c are stoppedby the body portion 12 as shown in FIG. 3.

[0021] It is noted that the present invention can be also used to removeother electrical elements mounted on the PCB 50 by through holesoldering.

[0022] A first advantage of the present invention is that the reworkingdevice can lift the socket connector such that the socket connector iscompletely detached from the PCB once the solder balls are heated toreflow.

[0023] A second advantage of the present invention is that the reworkingdevice lift the socket connector uniformly and without damaging the PCB.

[0024] It is to be understood, however, that even though numerouscharacteristics and advantages of the present invention have been setforth in the foregoing description, together with details of thestructure and function of the invention, the disclosure is illustrativeonly, and changes may be made in detail, especially in matters of shape,size, and arrangement of parts within the principles of the invention tothe full extent indicated by the broad general meaning of the terms inwhich the appended claims are expressed.

What is claimed is:
 1. A reworking device for removing an electricalelement soldered to a PCB from the PCB, comprising: a body portionarranged above the electrical element; a pair of standing legs for beinglocated on the PCB and supporting two opposite ends of the body portion;and a pair of movable clips movably assembled to the body portion, eachmovable clip forming a hook for hooking with the electrical element;wherein the movable clips have resilient members which can exert anupward force to the electrical element so that when a solderingconnection between the electrical element and the PCB is heated toreflow, the electrical element is pulled upwardly by the movable clipsto separate from the PCB.
 2. The reworking device as claimed in claim 1,wherein the hook is formed at a bottom end of the each of the movableclips for hooking at a protrusion formed at each of two opposite sidesof the electrical element.
 3. The reworking device as claimed in claim1, wherein the body portion defines a receiving hole at each of twoopposite ends thereof and each standing leg includes a post extendingthrough a corresponding through hole.
 4. The reworking device as claimedin claim 3, wherein the each of the standing legs includes an enlargedportion at a bottom end thereof for abutting against an upper surface ofthe PCB.
 5. The reworking device as claimed in claim 4, wherein a springis assembled to a corresponding post between the body portion and acorresponding enlarged portion of the standing leg.
 6. The reworkingdevice as claimed in claim 4, wherein a soft pad is located between thecorresponding enlarged portion and the PCB.
 7. The reworking device asclaimed in claim 1, wherein the body portion defines an elongate slotand each of the movable clips includes a pole through the slot.
 8. Thereworking device as claimed in claim 7, wherein each of the movableclips includes a first washer fixed at an upper portion of the pole, asecond washer fixed at the pole between the first washer and the hookand below the body portion, each of the resilient members being a springassembled to the pole and compressed between the first washer and thebody portion.
 9. The reworking device as claimed in claim 8, wherein athird washer is movably mounted to the pole and located between thespring and the body portion.
 10. A reworking device for removing anelectrical connector from a PCB to which the electrical connector issoldered, comprising: a pair of legs standing on the PCB and beside theconnector, each leg having a first spring thereon; a body portionmounted on the first springs of the legs and above the electricalconnector; at least a clip hanged on the body portion and having abottom end engaging with the electrical connector, a second springcompressed between the body portion and an upper end of the at least aclip, the second spring exerting an upwardly pulling force to theconnector via the bottom end of the at least a clip.
 11. In combination,a printed circuit board with an electronic component soldered thereon; areworking device including a body portion seated upon the printedcircuit board via at least one leg portion, thus spacing away from saidprinted circuit board with a constant distance, and a clip beingmoveable relative to the body portion at least along a verticaldirection, a biasing device urging said clip to move upwardly; whereinsaid clip defines a grasping section engaged with the electroniccomponent, so that once the electronic component is unsoldered, theelectronic component is raised upwardly away from the printed circuitboard by said biasing device while the body portion is still located atsubstantially the same vertical position relative to the printed circuitboard.